GEOLOGICAL FEATTJEES. 27 
The average width of these deposits is about one hun- 
dred and fifty miles. Proceeding northward from the 
Gulf toward the State of Tennessee, we find, underlying 
these formations, the eocene and cretaceous in Mississippi; 
the eocene, cretaceous, carboniferous, and upper Silurian 
and granite series in Alabama; the eocene, cretaceous, 
carboniferous, and granite series in Georgia ; the eocene, 
cretaceous, and granite series in South Carolina, Pro- 
ceeding from east to west in North Carolina, we find the 
alluvium, post-pliocene, miocene, eocene, cretaceous, granite 
series, and, near the junction with Tennessee, the lower 
Silurian roots. 
The State of Tennessee is more complicated .in its ge- 
ology than any other. Beginning at the western boundary, 
we find, at the low places on the Mississippi river, the 
alluvium and post-pliocene extending from the northern 
to the southern piirt of the State. Proceeding eastward,, 
we discover the eocene, underlaid successively by the Cre- 
taceous, the Devonian, the upper Silurian, and lower Si- 
lurian, till we reach the Cumberland mountains, where the 
last-mentioned formation is overlaid by the carboniferous 
group, including the coal itself. This coal is a part of the 
great Appalachian coal field, which extends in a south- 
western direction into northeastern Alabama. 
Texas and Arkansas present substantially the same va- 
riety as Alabama. 
MINERAL PRODIJCTIONS OF THESE STATES. 
The alluvium, post-pliocene, and cretaceous formations 
nowhere produce any massive or heavy minerals. The 
other formations bear the usual variety of minerals useful 
in arts and agriculture. 
